Infection caused by antibiotic-resistant microorganisms (ARMs) has been declared a global threat to public health. Polymeric nanoparticles (PNPs) formed by antimicrobial peptides (AMPs) and synthetic PNPs against ARM infections are emerging. PNPs are also considered to be a promising natural biological preservative that prevents microbial spoilage through food processing and preservation. We engineered CNMs, a novel nanocomposite antibacterial agent based on chitosan nanoparticles and AMP microcin J25. In this study, we aimed to evaluate the comprehensive antimicrobial activity, potential antimicrobial mechanism, and anti-inflammatory activity of CNMs. We demonstrated that CNMs harbor excellent bactericidal activity against clinical foodborne pathogens and ARMs. CNMs caused fast mortality against different growth phases of tetracycline (Tet)-resistant enterotoxigenic E. coli (ETEC) and significantly killed Tet-resistant ETEC in food biological environments. Mechanistically, CNMs have the ability to bind lipopolysaccharides (LPS), neutralize endotoxin, and promote diaphragm permeability by damaging the cell membrane. CNMs did not cause mouse RAW264.7 cell cytotoxicity. Notably, CNMs significantly reduced the cytotoxicity of RAW264.7 macrophages induced by LPS. The LPS-induced inflammatory response was significantly ameliorated by CNMs by reducing the levels of nitric oxide and proinflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-6, IL-8, IL-1β, Toll-like receptor 4, and nuclear factor κB (NF-κB), in LPS-challenged RAW264.7 macrophages. CNMs downregulated the NF-κB and mitogen-activated protein kinase signaling pathways, thereby inhibiting inflammatory responses upon LPS stimulation. Taken together, CNMs could be applied as effective antimicrobial/anti-inflammatory agents with lower cytotoxicity in food, medicine, and agriculture to prevent bacterial contamination and infection, respectively.

As one of the most harmful gases in the livestock house, ammonia is recognized as an environmental stressor by Environmental Protection Agency (United States). The study aimed to explore the effect of ammonia on hypothalamic-pituitary-ovarian (HPO) axis of rabbits. A total of ninety two-month-old female IRA rabbits were randomly divided into three groups, and were kept in animal environment control rooms for four weeks at college of animal science and technology, Hebei Agricultural University (Baoding, China). The rabbits in the control group were kept under ammonia concentration of < 3 ppm. The two treatment groups were kept under ammonia concentration of 30 ppm and 50 ppm. Hypothalamus, pituitary, and ovary were collected for hematoxylin and eosin (HE) staining, immunohistochemistry, terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Serum was collected for enzyme-linked immunosorbent assay (ELISA). Histopathological examination revealed that exposed to excess ammonia damaged the morphology and structure of hypothalamus, pituitary, and ovary. TUNEL assay revealed that apoptosis rate increased in hypothalamus, pituitary, and ovary. The protein expression levels of Bcl-2associated X protein (Bax) and Caspase-9 increased, while B-cell lymphoma-2 (Bcl-2) decreased, resulting in apoptosis. Moreover, the concentration of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (PROG) reduced in plasma. The mRNA expression of FSH and LH in pituitary and follicle-stimulating hormone receptor (FSHR), E2, PROG in ovary as well as decreased, indicated hormone secretion disorder. The results indicated that ammonia exposure damaged hypothalamus, pituitary, and ovary, caused hormone secretion disorder and apoptosis.

Enzymolytic soybean meal (ESBM) enriches free amino acids and small peptides, while mitigating anti-nutritional factors. Substituting soybean meal with ESBM enhances animal performance, though optimal piglet dietary supplementation levels vary. The present study aimed to assess the impact of ESBM on the growth performance, nutrient digestibility, antioxidative capacity and intestinal health of weaned piglets. A total of 120 piglets (initial body weight, 7.0 ± 0.4 kg) were randomly allocated into 4 dietary groups, each comprising 5 replicates with 6 piglets per replicate. The control group received the basal diet, while the experimental groups were fed diets containing 2, 4% or 8% ESBM as a replacement for soybean meal over 28 days. Compared with the control group, piglets supplemented with 4% ESBM exhibited a significant increase (p < 0.05) in average daily gain and the apparent total tract digestibility of dry matter, ether extract and gross energy (p < 0.05), alongside a notable decrease (p < 0.05) in diarrhea incidence. Fed ESBM linearly increased (p < 0.05) the villus height in the ileum of piglets. The levels of superoxide dismutase and total antioxidant capacity in serum of piglets increased (p < 0.05) in the 2 and 4% ESBM groups, while diamine oxidase content decreased (p < 0.05) in the 4 and 8% ESBM group. ESBM inclusion also upregulated (p < 0.05) the expression of superoxide dismutase 1 (SOD-1), Catalase (CAT) and claudin-1 mRNA. In terms of cecal fermentation characteristics, ESBM supplementation resulted in a increase (p < 0.05) in valerate content and a linear rise (p < 0.05) in propionate, butyrate, and total short-chain fatty acids levels, accompanied by a decrease (p < 0.05) in the concentrations of tryptamine and NH₃ in cecal digesta. ESBM had no discernible effect on cecal microbial composition. In summary, substitution of soybean meal with ESBM effectively improved the growth performance of piglets by enhancing nutrient digestibility, antioxidant capacity, intestinal barrier and cecal microbial fermentation characteristics, with the optimal replacement level identified at 4%.

In response to the urgent need for alternatives to antibiotics in poultry production, this study evaluated the effects of ursolic acid (UA), a plant-derived triterpenoid, on growth performance, metabolism, intestinal function, and antioxidant capacity in broilers. A total of 320 Cobb broilers were randomly divided into four groups: a control group and three groups supplemented with UA at 0, 50, 200, or 400 mg/kg of diet, with 8 replicates of 10 birds each, over a 42-day period. Body weight and feed intake were measured on days 21 and 42. On day 42, samples were collected for enzyme-linked immunosorbent assay (ELISA), untargeted metabolomics, hematoxylin–eosin (H&E) staining, meat quality assessment, and quantitative real-time PCR (qRT-PCR) analyses. Data were analyzed using one-way analysis of variance (ANOVA) in SPSS, and orthogonal contrasts were used to assess linear and quadratic responses to UA. The results showed that UA supplementation significantly enhanced growth and slaughter performance (P < 0.05), increased serum total protein (P < 0.05), and reduced serum triglycerides (P < 0.05). Untargeted metabolomics indicated that 200 mg/kg UA modulated lipid metabolism via α-linolenic acid and glycerophospholipid pathways. Additionally, this dose significantly improved the villus height-to-crypt depth ratio (VH/CD) and ileal protease activity (P < 0.05). Both 200 and 400 mg/kg UA reduced the b45min value of breast muscle (P < 0.05). Furthermore, UA supplementation elevated antioxidant enzyme activities in serum and ileum (P < 0.05). At the molecular level, 200 mg/kg UA upregulated expression of amino acid and fatty acid transporter genes, downregulated kelch-like ECH-associated protein 1 (KEAP1) (P < 0.05), and enhanced expression of catalase (CAT), superoxide dismutase 1 (SOD1), nuclear factor E2-related factor 2 (NRF2), and NAD(P)H: quinone oxidoreductase (NQO1) (P < 0.05). In conclusion, UA effectively improved growth performance, metabolic health, intestinal function, and antioxidant capacity in broilers, demonstrating its potential as a safe and effective alternative to conventional growth promoters in poultry production.

In modern poultry production, oxidative stress has emerged as a pivotal factor compromising the health status and overall performance of broiler. The aim of this study was to investigate the effects of dietary quercetagetin (QG) supplementation on hydrogen peroxide (H ₂ O ₂ )-induced oxidative damage in breast muscle of broilers, focusing on growth performance, meat quality, and antioxidant function, and elucidating the underlying mechanisms. Two hundred and forty one-day-old Cobb broilers were randomly divided into three treatment groups: the control group, the H ₂ O ₂ group and the H ₂ O ₂ + QG group. The control and H ₂ O ₂ groups were fed a basal diet, and the QG group was fed a basal diet supplemented with 100 mg/kg QG. The control group was intraperitoneally injected with normal saline, and the other two groups were treated with the same volume of 10% H ₂ O ₂ solution on day 37. The experimental period was 42 days. The results showed that H ₂ O ₂ -induced oxidative stress increased the levels of drip loss, cooking loss, reactive oxygen species (ROS), and oxidation products in the breast muscle, and damaged the mitochondrial function. Compared with the control group, the mRNA expressions of glutathione peroxidase ( GSH-Px ), NAD(P)H quinone dehydrogenase 1 ( NQO1 ), catalase ( CAT ), nuclear factor erythroid 2-related factor 2 ( Nrf2 ), transferrin receptor protein 1 ( TFR1 ), and ferritin heavy chain 1 ( FTH1 ) in the breast muscle were decreased ( p < 0.05). The addition of QG to the diet reduced the levels of ROS and oxidation products ( p < 0.05). Meanwhile, the addition of QG to the diet increased the mRNA expressions of Nrf2 and TFR1 , showing no significant difference from those of the control group. In conclusion, H ₂ O ₂ -induced oxidative stress impairs breast muscle quality, mitochondrial function, and antioxidant capacity in broilers. Dietary QG alleviates oxidative stress and improves meat quality by regulating the Nrf2 signaling pathway and ferroptosis-related mechanisms. This mechanism-based finding supports QG as a safe and effective dietary additive for broiler production, providing a practical solution to enhance animal health, stabilize meat quality, and promote the sustainability of intensive poultry farming.